jso: fix issues with JSSymbol

Inspired by PR #949

jso/apis/src/main/java/org/teavm/jso/core/JSSymbol.java

@@ -17,22 +17,28 @@
 
 import org.teavm.interop.NoSideEffects;
 import org.teavm.jso.JSBody;
-import org.teavm.jso.JSIndexer;
+import org.teavm.jso.JSClass;
 import org.teavm.jso.JSObject;
 import org.teavm.jso.JSPrimitiveType;
 
 @JSPrimitiveType("symbol")
+@JSClass
 public class JSSymbol<T> implements JSObject {
     private JSSymbol() {
     }
 
     @JSBody(params = "name", script = "return Symbol(name);")
+    @NoSideEffects
     public static native <T> JSSymbol<T> create(String name);
 
-    @JSIndexer
+    @JSBody(params = "obj", script = "return obj[this];")
+    @NoSideEffects
     public native T get(Object obj);
 
-    @JSIndexer
+    @JSBody(params = {"obj", "value"}, script = "obj[this] = value;")
     @NoSideEffects
     public native void set(Object obj, T value);
+
+    @JSBody(params = "obj", script = "return obj[this] !== void 0;")
+    public native boolean presentIn(Object obj);
 }

tests/src/test/java/org/teavm/jso/core/test/JSSymbolTest.java

@@ -0,0 +1,64 @@
+/*
+ *  Copyright 2024 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.jso.core.test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.teavm.jso.JSBody;
+import org.teavm.jso.JSObject;
+import org.teavm.jso.core.JSObjects;
+import org.teavm.jso.core.JSString;
+import org.teavm.jso.core.JSSymbol;
+import org.teavm.jso.core.JSUndefined;
+import org.teavm.junit.SkipJVM;
+import org.teavm.junit.TeaVMTestRunner;
+
+@RunWith(TeaVMTestRunner.class)
+@SkipJVM
+public class JSSymbolTest {
+    @Test
+    public void getWorks() {
+        var s = JSSymbol.create("customString");
+        var o1 = JSObjects.create();
+        var o2 = JSObjects.create();
+        writeSymbol(s, o1, JSString.valueOf("works"));
+
+        assertEquals(JSString.valueOf("works"), s.get(o1));
+        assertTrue(s.presentIn(o1));
+        assertEquals(JSUndefined.instance(), s.get(o2));
+        assertFalse(s.presentIn(o2));
+    }
+
+    @Test
+    public void setWorks() {
+        var s = JSSymbol.create("customString");
+        var o1 = JSObjects.create();
+        var o2 = JSObjects.create();
+
+        s.set(o1, JSString.valueOf("works"));
+        assertEquals(JSString.valueOf("works"), readSymbol(s, o1));
+        assertEquals(JSUndefined.instance(), readSymbol(s, o2));
+    }
+
+    @JSBody(params = { "symbol", "o", "value" }, script = "o[symbol] = value;")
+    private static native void writeSymbol(JSSymbol<Object> symbol, Object o, JSObject value);
+
+    @JSBody(params = { "symbol", "o" }, script = "return o[symbol];")
+    private static native JSObject readSymbol(JSSymbol<Object> symbol, Object o);
+}